The DOS Lander (Deep Sea Observatory System) represents a flexible platform for longer observations of the ocean floor using different sets of measuring devices. Besides of a sediment trap and various instruments to measure water temperature, salinity, current and turbidity it is equipped with a stereographic camera system to take high resolution images of the ocean floor.

The cameras and flashes are looking slightly downward in front of the lander. The frame rate was set to shoot images simultaneously every five minutes. Since we have two images from the same time point and with a big overlap, 3D-Models of the scene can be calculated later.

The night before its first deployment in the German license area Henri Robert from the Royal Belgian Institute of Natural Sciences came up with the idea to also put one of his amphipod traps in front of the camera system. Besides amphipod crustaceans, the trap catches organisms such as fish and other crustaceans, which are attracted by bait. Quickly the lander was extended using a couple of wooden sticks, cable ties and several meters of duct tape to fix the amphipod trap on the lander. Even though we weren’t 100% sure if we ever see the trap again, we stayed optimistic and kept our fingers crossed. The first deployment ended after one week and luckily Henri’s trap was still attached when the lander arrived on deck. Immediately afterwards we had a first look at the images. Obviously, the amphipod trap was a big attraction for the local community. It took only 10 minutes after the arrival on the sea bottom and the first fish, shrimps and, of course, amphipods appeared. We took around 1500 images during the first deployment with each camera. The images got annotated by our biologists on board. In the meantime the lander was prepared for its next mission only one day later. Batteries were charged and new configurations selected. Right now the DOS Lander is back on the ocean floor collecting data again. This mission will take two months and the lander will be recovered during the next Sonne cruise.